Electronic systems can include analog-to-digital (A/D) converters (ADCs). Converting analog signals to digital quantities allows processors in electronic systems to perform signal processing functions for the systems. Performance of ADC circuits can depend on environmental conditions such as temperature and on variations that can occur during manufacturing. A higher accuracy ADC circuit (e.g., in which the number of bits of the ADC circuit is twelve or greater) may need calibration multiple times during its working life to avoid bit weight errors. The present inventors have recognized a need for improved calibration of ADCs.